I had the stock 17" rims on my car and the car was running fine. I traded the stock rims for 19" AG 8.5 and 9.5 on Hankook 245/35/19 and 275/30/19 tires and now when the car accelerates I get a type of clunk noise and on deceleration another clunk. I am not sure if the AWD is not liking this combo or what but driving the car feels painful now. I am also lowered on KW v1 about 1.5 inch all around. I think there is some rubbing but im not sure if this is contributing to this type of 'clunk'. Has anyone had similar issues like this? Or know of things to try. I am going to try to raise it a little I guess but I am not positive that is the true problem.

if you are correct about the awd system not liking the setup i would guess it may be caused by the chosen tire sizes. i believe 235/35F and 265/30 is our recommended setup.
..as far as pulling te fuse out, i think that may have a damaging effect to our systems by making our the front axels and shaft take a load with out being ingaged? just seems damaging? anywho i hope my 2€ sounds valid and that your car gets back to par.

yeah i only ran it as a test ot figure out what was going on. the driveability was so bad it was clunking back and forth I just need to now find a solution to fix this. if it is indeed the tire ratios or is there an underlying issue. i thought people with XI's/lowered have run this size before. they are hankook tires so im not sure if that is the problem with just the sizes, i know there was a recommended size of 235/35 and 265/30 but could just those small differences have such a devastating effect??!?!??

I had the exact same problem,
I was running stock measure 225/40-18 and 255/35-18 but different brands,
used Michelin's front and new Hankook S1's rear.

The dealer always blamed them for not being RFT's,
showed me that by putting on all around 225-17 BMW RFT winter tyres the problem went away.
Of course they wanted to sell new BMW tyres.

They never said that the only reason was the different running diameters.

I then asked for a piece of electrical wire, about 2,10m long and measured the circumference on my own,
there was about 2,5cm less rear then front. Calculated this makes more than 1% difference.
This makes the system think that there is always wheelspin in the rear and engages the front drivetrain much harder as effectively needed.
Together with the sloppy tranny bushings you get a nice plop.
The xdrive system also reacts to this difference and tries to compensate, but mechanically this is not possible as there is no center diff.
My car was almost undriveable, when xdrive engaged the front pulled more than the rear was pushing and reacted unpredictabely with lots of understeer.

I had the exact same problem,
I was running stock measure 225/40-18 and 255/35-18 but different brands,
used Michelin's front and new Hankook S1's rear.

The dealer always blamed them for not being RFT's,
showed me that by putting on all around 225-17 BMW RFT winter tyres the problem went away.
Of course they wanted to sell new BMW tyres.

They never said that the only reason was the different running diameters.

I then asked for a piece of electrical wire, about 2,10m long and measured the circumference on my own,
there was about 2,5cm less rear then front. Calculated this makes more than 1% difference.
This makes the system think that there is always wheelspin in the rear and engages the front drivetrain much harder as effectively needed.
Together with the sloppy tranny bushings you get a nice plop.
The xdrive system also reacts to this difference and tries to compensate, but mechanically this is not possible as there is no center diff.
My car was almost undriveable, when xdrive engaged the front pulled more than the rear was pushing and reacted unpredictabely with lots of understeer.

Take a wire an test on your own,
then get the correct tire measure.

i think with my tire size im at the 1% difference as well. were you able to fix your issues with just new tires?

I had the stock 17" rims on my car and the car was running fine. I traded the stock rims for 19" AG 8.5 and 9.5 on Hankook 245/35/19 and 275/30/19 tires and now when the car accelerates I get a type of clunk noise and on deceleration another clunk. I am not sure if the AWD is not liking this combo or what but driving the car feels painful now. I am also lowered on KW v1 about 1.5 inch all around. I think there is some rubbing but im not sure if this is contributing to this type of 'clunk'. Has anyone had similar issues like this? Or know of things to try. I am going to try to raise it a little I guess but I am not positive that is the true problem.

jumping to a 285/ 30 in the rear would make both overall diameter 25.8 inches. or dropping down to a 235 35 front would make it 25.5 vs the 275 30 rear at 25.6